What is the recommended dosing of vitamin D2 (Vitamin D2) for an 18-year-old with vitamin D deficiency?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: July 2, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

For an 18-year-old with vitamin D deficiency, the recommended dosing of vitamin D2 is typically 50,000 IU once weekly for 8 weeks, followed by a maintenance dose of 800 IU/day, as suggested by the most recent and highest quality study 1. The goal of treatment is to achieve a 25(OH)D level of at least 30 ng/mL, which is essential for maintaining bone health and preventing complications associated with vitamin D deficiency.

  • The initial high-dose regimen of 50,000 IU weekly for 8 weeks is necessary to rapidly replenish depleted vitamin D stores, as vitamin D is fat-soluble and stored in body tissues.
  • After the initial treatment period, the patient should have their vitamin D levels rechecked to ensure the deficiency has been corrected, and the maintenance dose can be adjusted accordingly.
  • It is also important to note that adequate calcium intake, of at least 1,000-1,200 mg daily, should accompany vitamin D supplementation to support bone health, as suggested by 1.
  • Additionally, taking vitamin D with meals containing some fat can improve absorption, and severe deficiency may require longer treatment or higher doses under medical supervision, as noted in 1.
  • While some evidence suggests that vitamin D3 may be more effective for long-term supplementation, vitamin D2 is still a viable option, especially for patients with specific dietary restrictions or preferences, as mentioned in 1.

From the Research

Recommended Dosing of Vitamin D2 for Deficient Vit D at 18

  • The recommended dosing of vitamin D2 for an 18-year-old with vitamin D deficiency is not explicitly stated in the provided studies, but some studies provide guidance on vitamin D2 dosing for adults with vitamin D deficiency 2, 3.
  • According to a study published in the American Family Physician, treatment of vitamin D deficiency may include oral ergocalciferol (vitamin D2) at 50,000 IU per week for eight weeks 2.
  • Another study published in the Annals of Saudi Medicine compared the effect of a 10-day course of high-dose calciferol versus a single mega dose of ergocalciferol in correcting vitamin D deficiency, and found that a single mega dose of 600,000 IU D2 was less effective than a 10-day course of 500,000 IU D3 3.
  • It is essential to note that the effectiveness of vitamin D2 supplements may be lower compared to vitamin D3 supplements, and vitamin D2 may enhance the degradation of 25-hydroxyvitamin D3 (25[OH]D3) metabolite 3.

Considerations for Dosing

  • The dosing of vitamin D2 should be individualized based on the severity of vitamin D deficiency, body weight, and other factors 4.
  • A study published in the European Journal of Endocrinology developed a practical cholecalciferol loading dose regimen, which may be useful for guiding vitamin D2 dosing 4.
  • However, it is crucial to consult with a healthcare professional to determine the appropriate dosing regimen for an 18-year-old with vitamin D deficiency, as the optimal dosing strategy may vary depending on individual circumstances 2, 5, 6.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.